The overall objective of this proposed research program is to explore and evaluate the potential of local bloodsucking arthropods to serve as intermediate hosts for filariea of animals and man. Particular emphasis will be placed on arthropods other than mosquitoes, namely species of Culicoides, Simulium, and Chrysops. Wild-caught insects will be fed on filaria-infected nonhuman primates or local mammals. The filariea available for these vector potential studies include Loa loa, Onchocerca volvulus, Dipetalonema vanhoofi (=D. perstans), and an array of dipetalonematid species, e.g., D. marmosetae, D. procyonis, etc., that naturally-occur in monkeys or local mammals. The intermediate host capability of each arthropod species will be evaluated by (1) studying the morphological development of larvae in the host, and (2) using sectioned material to determine the target tissues utilized by larvae for development. This also will provide information about the migratory behavior of the larvae. When appropriate, attempts to complete the life cycle will be undertaken. Through this research program it is expected that an array of arthropod species will be identified as suitable laboratory intermediate hosts for non-mosquito transmitted filarial studies.